JPH01230705A - Manufacture of reinforced fiber-contained aluminum alloy powder - Google Patents

Abstract

PURPOSE:To simply obtain reinforced fiber-contained Al alloy powder without any hindrance on manufacturing by bringing uneven surface of a rotary body into contact with molten Al alloy dispersing whisker or staple of ceramic and scattering and solidifying the molten metal. CONSTITUTION:In the molten Al alloy 2 uniformly dispersed by charging and stirring the reinforced fiber of whisker of SiC, etc., staple, etc., of C, etc., into the molten Al alloy, the rotary drum 3 having the gear-like rugged part 4 on the whole peripheral side face is dipped while rotating, to scatter the above molten metal 2 dispersing the reinforced fiber. The scattered molten metal 2 is solidified at >=10<3> deg.C/sec cooling speed, to manufacture the above alloy powder. Then, the whisker or staple is desirable to disperse in the molten Al alloy 2 at about 5-40vol.%. Further, particle size of the obtd. powder is desirable to be <= about 3mm. By such method, the above powder uniformly dispersing the reinforced fiber without any orientation and having fine structure can be simply manufactured without any hindrance on the manufacturing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing A2 alloy powder containing reinforcing fibers, which is used for producing fiber-reinforced aluminum (AQ) alloys.

[Conventional technology]

In order to improve strength and reduce elongation while taking advantage of the toughness and ductility of metals, attempts have been made to disperse ceramic reinforcing fibers into the metal matrix, resulting in lightweight and low melting point A.
! Or some fiber reinforced metals (FRM) centered on Ae gold alloy
) has been proposed.

The method for manufacturing this fiber-reinforced metal includes (1) l! A method of mixing alloy powder and reinforcing fibers such as whiskers or short fibers and sintering or extruding the mixture, and (2) a method of injecting and permeating molten A2 alloy at high pressure into a billet containing hardened reinforcing fibers are known. ing.

However, in the method (1), it is difficult to uniformly disperse the reinforcing fibers, and the sinterability is decreased, resulting in a large number of voids, making it difficult to obtain a dense product. A2 in a solvent such as acetone
Although uniform dispersion can be obtained by mixing alloy powder and reinforcing fibers, sinterability is not improved and the process is complicated and costs are high. In addition, since rapid solidification is not possible in method (2), a high alloy of 1 cannot be used, and there is a problem in the wettability of the ceramic reinforcing fibers and the molten AR alloy, making it difficult to obtain a strong bond.

As you can see, there are still many problems with fiber-reinforced metals.
At present, it has not been put into practical use.

[Problem to be solved by the invention]

The present inventors have overcome the above-mentioned problems of fiber-reinforced metals,
As a result of repeated studies in order to provide a fiber-reinforced A [alloy with reinforced fibers that are uniformly dispersed, dense, and have excellent strength, we changed the conventional idea of mixing A2 alloy powder and reinforcing fibers, and created a single alloy. The idea was to include reinforcing fibers in the powder in advance.

However, when using the conventional gas atomization method, which is a common method for manufacturing Aff alloy powder, the nozzle becomes clogged due to reinforcing fibers dispersed in the molten Aff alloy.
Powder production proved impossible.

Therefore, the present invention uses a method other than the gas atomization method.
Reinforcing fiber-containing A is made from molten A2 alloy by dispersing reinforcing fibers.
f! The object of the present invention is to provide a method for producing alloy powder.

[Failure to solve the problem]

The method for producing reinforcing fiber-containing aluminum alloy powder of the present invention includes dispersing ceramic whiskers or short fibers in a molten aluminum alloy, and bringing the molten metal into contact with the uneven portion of a rotating body having an uneven portion on its circumferential surface. The method is characterized in that the molten metal is scattered and solidified at a cooling rate of 103 tZ'/cap or more.

However, the reinforcing fiber-containing aluminum alloy powder of the present invention obtained by this method contains 5 to 40% by volume of ceramic whiskers or short fibers, and has a diameter of -44-3all.
It is characterized by the following:

There are no particular restrictions on the AQ alloy used in the present invention; for example, A2
-3i alloy, A+! -3i-Fe-Ni alloy, AR-S
i-Fe-Ni-Cu-Mg alloy and Al! -F
e-Ni-Cr-Mo alloy etc. can be used.

Ceramic reinforcing fibers may be commonly used whiskers or short fibers, such as whiskers of alumina, silicon carbide, graphite, potassium titanate, etc., and short fibers of alumina, alumina-silica, zirconia, carbon, etc. be. The dimensions of the reinforcing fibers are that the whiskers generally have a diameter of 0.5 to 1 μm and the length of about 50 to 200 μm, and the short fibers have a diameter of 0.5 to 10 μm and a length of jI′1.
1 or less is common. This length is limited by the particle size of the powder to be manufactured, but it can be made finer by adjusting the length to a certain level or less before dispersing it into the molten metal, or by stirring the molten metal using longer whiskers or short fibers. .

Some of these reinforcing fibers have poor wettability with AQ alloys, or some, such as carbon, react with Ae at high temperatures, so if necessary, they may be treated with substances that improve wettability, such as high-melting point metals, or It may be coated in advance with a substance that can prevent reaction, such as TiC.

[Effect]

In the method of the present invention, whiskers and short fibers are dispersed in the molten A2 alloy, but the whiskers and short fibers are uniformly dispersed without precipitation. Next, this molten metal is rapidly cooled and solidified by scattering it on an uneven part (for example, a gear shape) of a rotating roller or drum. Therefore, in the resulting 19 alloy powder, whiskers or short fibers are uniformly dispersed, their orientation is directionless, and the structure is fine, making it possible to obtain a powder in an extremely desirable state.

The reason why the content of whiskers or short fibers in the A1 alloy powder is 5 to 40% by volume, that is, the amount of whiskers or short fibers dispersed in the AR alloy melt is 5 to 40% by volume. This is because even if it exceeds 40% by volume, the strength-improving effect is saturated and it is uneconomical.

The particle size and yield of the obtained A2 alloy powder can be arbitrarily controlled by the rotational speed of the rotating body, the depth of immersion into the molten metal, the shape of the uneven parts of the rotating body, etc. However, the particle size of the powder should be no more than 3IIj;
If it is larger than this, it is difficult to solidify at a cooling rate of 103C/sec or more.

The reinforcing fiber-containing A2 alloy powder of the present invention can be used as it is as a raw material for general powder metallurgy, and a fiber-reinforced A9 alloy can be produced using conventional equipment and methods. In particular, when hot forging is used, the orientation is random, so it is suitable for parts that require strength in all directions.
In the case of hot extrusion, the reinforcing fibers are oriented in the extrusion direction, so it is suitable for manufacturing parts that require strength in the extrusion direction.

〔Example〕

The reinforcing fibers shown in Table 1 were respectively introduced into the molten metal of Aff alloy (2014) and stirred to uniformly disperse them.

Table 1 130 volume% SiC whiskers (diameter 0.5 μm length 30 μm) 210 volume% Ap203 short fibers (diameter 3
μm length 200 μm) 320 volume% (
Diameter 3μm Length 200μm) 430% by volume
(Diameter: 3 μm, length: m) 535 volume%
(Diameter: 3 μm, length: 2 (6) m) The reinforcing fibers listed in Table 1 were dispersed in a carton molten metal container l as shown in the figure. A in which molten alloy 2 was added and the reinforcing fibers were dispersed.
A rotary drum 3 having gear-shaped uneven portions 4 on the entire circumferential side surface was immersed in the Q alloy molten metal 2 while rotating in the direction of the arrow, and the A9 alloy molten metal 2 in which reinforcing fibers were dispersed was scattered in the direction of the dotted arrow. . At this time, the diameter of the rotating drum 3 is 25 cm, the height from the groove to the top of the uneven part 4 is 5n, and the maximum immersion depth of the top of the uneven part 4 is about 2n. The rotation speed was 5000 rpm. The A2 alloy molten metal with dispersed reinforcing fibers is approximately 105C.
AQ alloy powder containing reinforcing fibers with an average particle size of about Q, 5a+m was obtained by rapid solidification at a cooling rate of /sec.

Using 60 meshes or less of the obtained reinforcing fiber-containing A2 alloy powder, cold press molding was performed at a pressure of 4 ton/Crn2, and this was then molded at a temperature of 500C and at a pressure of 4 ton/C.
A fiber-reinforced A alloy was produced by hot pressing and solidifying at a pressure of m2. After each alloy was subjected to T6 treatment, the porosity and tensile strength at room temperature were measured.

For comparison, fiber-reinforced AQ gold alloys of exactly the same composition were manufactured according to conventional methods. That is, (a) mixed powder obtained by dry mixing A, ff alloy powder and reinforcing fiber in a speed mixer for 1 hour, and (b) mixed powder obtained by mixing A17 alloy powder and reinforcing fiber in an acetone solvent and then evaporating the solvent. The process was carried out in the same manner as above, except that

Each conventional alloy was also subjected to T6 treatment, and then its porosity and tensile strength at room temperature were measured. The results are shown in Table 2.

Table 2 Fiber reinforcement A using reinforcing fiber-containing A2 alloy powder of the present invention
1! It can be seen that the alloy has superior strength to the fiber-reinforced A2 alloy produced using a conventional mixed powder of A9 alloy powder and reinforcing fibers.

〔Effect of the invention〕

According to the present invention, it is possible to easily and inexpensively provide A2 alloy powder containing reinforcing fibers for all types of Ae composites without any production problems such as nozzle clogging in conventional gas atomino methods.

Therefore, by using the reinforcing fiber-containing A2 alloy powder of the present invention, a fiber-reinforced A2 alloy having uniformly dispersed reinforcing fibers, dense structure, and excellent strength can be produced by ordinary powder metallurgy.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view showing a specific example of an apparatus for producing reinforcing fiber-containing A2 alloy powder by the method of the present invention. 1... Molten metal container 2... AR alloy molten metal + reinforcing fiber 3... Rotating drum 4... Uneven part

Claims (3)

[Claims] (1) Ceramic whiskers or short fibers are dispersed in a molten aluminum alloy, and the molten metal is scattered by contacting the molten metal with the uneven parts of a rotating body having an uneven part on its circumferential side, and heated to 10^3°C. /sec. A method for producing reinforcing fiber-containing aluminum alloy powder, which comprises solidifying at a cooling rate of at least 100%. (2) The method for producing reinforcing fiber-containing aluminum alloy powder according to claim (1), wherein 5 to 40% by volume of whiskers or short fibers are dispersed in the molten aluminum alloy. (3) Claim in which the particle size of the obtained powder is 3 mm or less (
1) The method for producing reinforcing fiber-containing aluminum alloy powder as described above.